What is the name of the compound [Fe(H2O)5(SCN)]Cl2? 

(a) pentaaquathiocyanatoiron(III) chloride 

(b) pentaaquachlorothiocyanato iron(III) 

(c) pentaaquathiocyanatoiron(III) dichloride

(d) pentaaquathiocyanatoiron(II) chloride

Video transcript

All right. Hi, everyone. So for this question, let's give the name of the following complex R un H 34, no 22 BR two. Option A says tetra ammonia, di nitro ruthenium for bromine. Option B says di nitro tetra amine rum to bromide. Option C says tetra amine di nitro rhenium for bromide. And option D says tetra amine di nitro reum two bromide. So recall really quickly that coordinations compounds or complexes are composed of two main parts. Number one is the complex ion and the second part is the counter ion. Now, the complex ion is made up of a metal cion in the center that is connected to other molecules or ions referred to as ligands. So the counter ion, the counter ion exists to balance the charge of the compound overall and make it neutral. So when it comes to naming co ordination compounds, the metal cion is written before the nonmetal anion. And it just so happens that our metal cion is rheum, which is a transition metal. Therefore, we have to indicate or specify its positive charge using a Roman numeral. And there should only be a space in the name in between the name of the cion and the name of the anion. So if we consider the structure that we're given, first and foremost, right, we happen to have two ions of bromide each with a charge of negative one. So because there are two bromide ions, the total charge of the counter ion is going to be negative too, which means that the charge of the complex ion is going to be plus two to make sure that the compound is neutral overall. And so the name of the counter ion in this case is going to be bromide. So based off this alone, I can actually go ahead and eliminate option a of the multiple choice because the counter ion is listed as bromine and not bromide. So now we can go ahead and focus our attention on the complex ion. And because rhenium happens to be a transition metal, we first have to find the oxidation state of ruthenium in this case. And to do so, we have to go ahead and really quickly recall what ligands we have connected to ruin in the Senate. In this case, we have ammonia, which happens to be neutral and therefore has an oxidation state of zero while we also have nitro lit, which is an anion or an anionic ligand and therefore has an oxidation state of negative one. So we can use this information to sulfur, the oxidation state of ruthenium. After recalling the fact, the charge of the complex is the total oxidation number of the complex itself. So what that means right is that the oxidation state of rhenium together with the oxidation state that each of my ligands has to equal the charge of my compound, which happens to be plus two. And I also have to add in the number of each, right. So I'm going to add in the oxidation states of both of my ligands while also taking into consideration the quantity of each ligand that I happen to have. So that when I find the sum of everything, I should get a total of plus two, which is the charge of my overall complex ion, right? So in this case, I can substitute zero for the oxidation state of ammonia and I can substitute negative one for the oxidation state of my natural group or my natural legends. Here I end up was zero from ammonia. So I get the following right. Two, subtracted from the oxidation state of ruthenium gives me a total charge of positive two, which means that the oxidation state of ruthenium is going to be positive four. Therefore, the name of my medal is going to be Ruthenia with a Roman numeral or afterwards. So now before the name of the transition metal itself, I'm going to place my legends in alphabetical order beforehand. So generally speaking, right, neutral ligands tend to carry their normal name except for ammonia because ammonia is referred to as a mean with two M's. And in addition to this prefixes are added before the name of each ligand to identify their quantity in the complex itself, right? So the presence of ammonia indicates that my ligand is going to be known as a mean and because I have four of them, it will be tetra a me. Now here, my anionic ligand is referred to as Nitro because an anionic ligand is going to drop the ID as the suffix because it's going to be replaced with an O at the end, right? So if the original name of the anion is nitrite, it will be referred to as Nitro in this case. And because I have two in my actual structure, this means that I'm going to write die Nitro in the name of my complex. So then if I scroll down one more time to give myself some space, my ligands are going to be listed in alphabetical order according to their name, right? So a mean goes before Nitro, which means that it's going to be tetra Amine, oops die Nitro Rusin four. And then I add a space before I go ahead and list my counter ion which is bromide and there you have it, right? My complete name is going to be Tetra Amine di Nitro rheum four bromide, which means that if I scroll upwards here, my answer is going to be option C in the multiple choice. So with that being said, if you stuck around to the end. Thank you so very much for watching and I hope we found this helpful.